Frameless interior rearview mirror assembly

Abstract

An interior rearview mirror assembly for a vehicle includes a mirror casing and a prismatic interior reflective element. The reflective element comprises a wedge-shaped glass substrate having a perimeter edge about a periphery of the glass substrate and extending between first and second surfaces thereof. The glass substrate has a mirror reflector established at the second surface. A front surface of the perimeter edge provides a smooth curved transition at the perimeter edge between a perimeter region of the first surface and the mirror casing. The front surface of the perimeter edge is rounded with a radius of curvature of at least about 2.5 mm. No portion of the mirror casing encompasses the first surface of the glass substrate.

The invention claimed is: 
     
       1. An interior rearview mirror assembly for a vehicle, said interior rearview minor assembly comprising:
 a mirror casing; 
 a prismatic interior reflective element; 
 wherein said prismatic interior reflective element comprises a wedge-shaped glass substrate having a first surface and a second surface and a perimeter edge about a periphery of said wedge-shaped glass substrate and extending between the first and second surfaces thereof, said wedge-shaped glass substrate having a mirror reflector established at the second surface thereof, the first surface facing a driver of a vehicle when said interior rearview mirror assembly is normally mounted in a vehicle equipped with said interior rearview mirror assembly; 
 wherein a front surface of the perimeter edge provides a smooth curved transition at the perimeter edge between a perimeter region of the first surface of said wedge-shaped glass substrate and said mirror casing; 
 said perimeter region circumscribing said wedge-shaped glass substrate; 
 wherein the front surface of the perimeter edge comprises a rounded curved surface disposed between the first surface of said wedge-shaped glass substrate and said mirror casing; 
 wherein the radius of curvature of the front surface of the perimeter edge is at least 2.5 mm; 
 wherein no portion of said mirror casing encompasses the first surface of said wedge-shaped glass substrate; and 
 wherein an outer part of the perimeter edge of said wedge-shaped glass substrate is co-planar with an outer part of a side wall of said mirror casing. 
 
     
     
       2. The interior rearview mirror assembly of  claim 1 , wherein the radius of curvature of the front surface of the perimeter edge is uniform around the perimeter of said wedge-shaped glass substrate. 
     
     
       3. The interior rearview mirror assembly of  claim 1 , wherein said prismatic interior reflective element is adhered to said mirror casing. 
     
     
       4. The interior rearview mirror assembly of  claim 1 , wherein said mirror casing comprises a planar attachment surface, and wherein said prismatic interior reflective element is attached at said attachment surface of said mirror casing to secure said prismatic interior reflective element to said mirror casing. 
     
     
       5. The interior rearview mirror assembly of  claim 1 , wherein the radius of curvature of the front surface of the perimeter edge is non-uniform around the perimeter of said wedge-shaped glass substrate. 
     
     
       6. The interior rearview mirror assembly of  claim 5 , wherein the perimeter edge of said wedge-shaped glass substrate comprises a thicker region and a thinner region, and wherein the radius of curvature along the thinner region of the perimeter edge of said wedge-shaped glass substrate is smaller than the radius of curvature along the thicker region of the perimeter edge of said wedge-shaped glass substrate. 
     
     
       7. The interior rearview mirror assembly of  claim 1 , wherein said prismatic interior reflective element comprises a user input portion, said user input portion operable to detect the presence or touch of a human finger at the first surface of said wedge-shaped glass substrate, said user input portion comprising at least one capacitive touch sensor disposed at and behind the second surface of said wedge-shaped glass substrate. 
     
     
       8. The interior rearview mirror assembly of  claim 7 , wherein said at least one capacitive touch sensor comprises a plurality of capacitive touch sensors at said user input portion, and wherein circuitry of said interior rearview mirror assembly is operable to limit accidental actuation of a capacitive touch sensor that is adjacent to any one of said plurality of capacitive touch sensors.